textproduct: Rapid City

KEY MESSAGES

- Near-critical fire weather conditions Friday

- Another round of colder temperatures and chance for precipitation return over the weekend

DISCUSSION

(This Evening Through Thursday) Issued at 134 PM MST Thu Feb 26 2026

Current upper air water vapor analysis depicts split-flow over western/central CONUS and Canada. A ridge is positioned over the West Coast stretching from OR down to Baja California, a broad trough is positioned over eastern CONUS stretching from the Hudson Bay down to FL, and a shortwave aloft with a surface-low positioned over central Saskatchewan. WV indicates a few high clouds moving across western SD in association with the northern portion of the split-flow. The main concern for this forecast is focused on the fire weather conditions that will be present today and Friday. Surface observations currently show west to northwest winds over northwestern SD with gusts reaching 41 mph, temperatures in the 40s and 50s, and RH values mainly in the 20s percent range. Fire weather conditions are expected to remain elevated through 0Z, this evening, before winds begin to diminish and RH values begin to recover.

Tonight into Friday, the surface-low will slide further to the southwest into western Ontario, brining with it a cold front that will move into the forecast region Friday afternoon. Ahead of the front, gusty northwest winds will develop over northwest SD, with some gusty locations in central/south-cental SD. Wind gusts are expected to be strongest over northwest SD with the greatest chances for >40 mph occurring midday (~35 to 55 percent chance, via NBM- CONUS). RH values for northwestern SD will not be at Red Flag Warning levels due to increasing cloud cover throughout the day, however, fuels are cured and ready to burn if an ignition source is present. Other locations of fire weather concern are: 1) southwestern SD where highs will be in the low 60s, RH values between 15 and 20 percent, and winds gusting between 20 and 30 mph, and 2)south-cental SD where highs will be in the high 50s, RH values in the low 20s, and winds gusting between 25 and 35 mph. Due to these near-critical fire weather conditions, a Red Flag Warning is being considered for south-central and southwestern SD for midday into the afternoon Friday.

Friday night into Saturday will see the cold front slide through the region, brining increased chances for precipitation to northwestern and central SD, along with colder temperatures, increased RH values, and winds becoming north/northeasterly. Current model analysis shows the best chance for snow accumulation along the ND/SD border (~30 to 50 percent chance for >1 inch, via NBM-CONUS). Due to model disagreement, confidence on the exact track of the snow band is moderate.

For next week, warmer temperatures will return along with increased chances for precipitation later in the week.

AVIATION

(For the 00Z TAFS Through 00Z Friday Evening) Issued At 429 PM MST Thu Feb 26 2026

Northwest winds will taper off after 00-02z across the SD plains. Winds will pick up after 16-18z Thursday morning with gusts to 30 knots, strongest winds from KRAP through NW SD.

VFR conditions are expected through the period.

FIRE WEATHER

Issued At 134 PM MST Thu Feb 26 2026

Unseasonably mild temperatures, dry air, and breezy to gusty winds are expected Friday across far southwest and south-central South Dakota. Minimum relative humidity values are forecast to drop to around 17 percent, with winds gusts of 20 to 35 mph. This combination could result in near-critical fire weather conditions. These conditions are expected to develop by late morning and persist through the afternoon.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Fire Weather Watch from Friday morning through Friday afternoon for SDZ322-335. WY...None.